Seems like you are thinking on upgrading your current plan but right now it’s not possible.
We are working to allow our users to be able to upgrade their plan on the go having app built-in options. We still have no date for this feature but will be available during 2024.
Meanwhile, if you are out of the refund period, the only option is to cancel the automatic renewal of your subscription, wait to expire your license and sign for a different subscription plan.